The invention relates to a protective breathing mask for covering the mouth and nose of a wearer thereof, to provide protection from harmful substances or components that may be present in the air being breathed in.
One form of such a breathing mask is of a multi-layer construction, comprising an outer layer, an inner layer and a filter element therebetween, as disclosed for example in German patent specification No 3 113 828. That mask is used for filtering out contaminating material in particulate form in the air being breathed and for that purpose comprises an outer layer consisting of a hot-deformable plastic material. Likewise the inner layer in that mask may also comprise a hot-deformable plastic material while the filter element between the outer and inner layers is formed by a fibre fleece or non-woven fibre material. The fact that the mask is formed from inner and outer layers of deformable plastic material means that it is relatively expensive to produce. Another disadvantage of that mask is that it takes up a certain amount of space at all times, and cannot be collapsed or folded down to produce a compact item when not in use. Furthermore, that mask is not suitable, or is suitable only to a very limited extent, for removing gaseous noxious substances from the air being breathed in.
A half-mask for filtering out particles and consisting of a soft polymer foam is disclosed in German patent specification No 3 434 357. Although that mask can be folded down and collapsed to provide a compact article when not in use, it is however intended only for filtering out particulate materials and is not suitable for also filtering gaseous materials.